In celebration of the 150th anniversary of William Huggins’ famous observation of the monochromatic emission lines in the Cat’s Eye planetary nebula on 29th August 1864.
http://www.skyandtelescope.com/astronomy-news/observing-news/first-planetary-nebula-spectrum-08142014/
I recorded (a day late unfortunately due to cloud) the H alpha and N[II] forbidden lines at high resolution using my LHIRES III spectrograph (resolution 0.35 Angstrom)
http://www.spectro-aras.com/forum/download/file.php?id=1691&sid=ee1a3c5ffd6e4e48c8d1019c32631b27
The spectrum is a narrow vertical slice through the nebula at each wavelength. At this much higher resolution than available to Huggins, the lines are significantly broadened by the doppler effect showing interesting variations in velocity at different latitudes of the nebula.
Robin
http://www.threehillsobservatory.co.uk